Brief Article
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World J Gastroenterol. Nov 28, 2011; 17(44): 4905-4910
Published online Nov 28, 2011. doi: 10.3748/wjg.v17.i44.4905
Prognostic role of sensitive-to-apoptosis gene expression in rectal cancer
Sevgi A Ozden, Hazan Ozyurt, Zerrin Ozgen, Olca Kilinc, Mustafa Oncel, Aylin E Gul, Nimet Karadayi, Nedime Serakinci, Beki Kan, Oya Orun
Sevgi A Ozden, Hazan Ozyurt, Clinic of Radiation Oncology, Dr. Lütfi Kırdar Kartal Education and Research Hospital, 34890 Istanbul, Turkey
Zerrin Ozgen, Clinic of Radiation Oncology, Medical Park, 81060 Istanbul, Turkey
Olca Kilinc, Beki Kan, Oya Orun, Department of Biophysics, Marmara University School of Medicine, 34668 Istanbul, Turkey
Mustafa Oncel, Clinic of Surgery, Dr. Lütfi Kırdar Kartal Education and Research Hospital, 34890 Istanbul, Turkey
Aylin E Gul, Nimet Karadayi, Department of Pathology, Dr. Lütfi Kırdar Kartal Education and Research Hospital, 34890 Istanbul, Turkey
Nedime Serakinci, Telomere Aging Group, Center for IRS, Southern Denmark University, 7100 Vejle, Denmark
Nedime Serakinci, Faculty of Medicine, Near East University, 922022 Lefkosa, Mersin 10, Turkey
Beki Kan, Department of Biophysics, Acıbadem University School of Medicine, 34848 Istanbul, Turkey
Author contributions: Ozden SA designed the study, treated the patients, analyzed the data and wrote the manuscript; Ozyurt H and Ozgen Z assisted Ozden SA in the clinical follow-up and treatment evaluations of the patients; Oncel M provided the biopsy tissues and Gul AE and Karadayi N conducted the pathological investigations; Serakinci N and Kan B gave technical support and conceptual advice and edited the manuscript; Ozden SA and Kilinc O performed the molecular biology experiments and collected the data; Orun O gave technical support, analyzed data, supervised the project and wrote the manuscript.
Supported by Marmara University Research Fund, No. SAG-DKR-140305-0089
Correspondence to: Oya Orun, PhD, Assist Professor, Department of Biophysics, Marmara University School of Medicine, 34668 Istanbul, Turkey. oakalin@marmara.edu.tr
Telephone: +9-216-3480585 Fax: +9-216-3480585
Received: April 21, 2011
Revised: June 21, 2011
Accepted: June 28, 2011
Published online: November 28, 2011
Abstract

AIM: To investigate the association between prognosis of rectal cancer treated with chemoradiotherapy (CRT) and expression of sensitive-to-apoptosis (SAG), B-cell lymphoma-extra large (Bcl-XL) and Bcl-2 homologous antagonist/killer (Bak).

METHODS: Real-time quantitative polymerase chain reaction was used to determine the expression of proteins of interest, namely SAG, Bcl-XL, Bak and β-actin, in rectal carcinoma patients who had a follow-up period of 3 years after CRT. Biopsy specimens were excised from the rectal tumor preceding CRT.

RESULTS: SAG, Bcl-XL and Bak proteins showed significant correlations with each other. In multivariate analysis, patients with high vs low SAG expression showed a statistically significant difference in 2-year survival rates: 56% vs 73%, respectively (P = 0.056). On the other hand, there were no significant correlations between the expression levels of all three genes and metastatic rates or tumor responses to CRT. Mean overall survival in the patients with elevated SAG expression was 27.1 mo ± 3.9 mo [95% confidence interval (CI): 19.3-34.9], and in patients with reduced expression, it was 32.1 mo ± 2.5 mo (95% CI: 27.3-36.9). The corresponding values for Bcl-XL were 28.0 mo ± 4.1 mo (95% CI: 19.9-36.1) and 31.7 mo ± 2.9 mo (95% CI: 26.0-37.5), and those for Bak were 29.8 mo ± 3.7 mo (95% CI: 22.5-37.2) and 30.6 mo ± 2.4 mo (95% CI: 25.5-35.0), respectively.

CONCLUSION: Two-year survival rates significantly correlated with low SAG expression, and SAG may be a candidate gene for good prognosis, independent of therapeutic response of different individuals.

Keywords: Sensitive-to-apoptosis gene; Sensitive-to-apoptosis; Rectal cancer; B-cell lymphoma-extra large; Bcl-2 homologous antagonist/killer; Apoptosis